Running a CMSIS-DSP-Library function from RAM

lpcware — Thu, 16 Jun 2016 01:33:08 GMT

Content originally posted in LPCWare by g_mocken on Wed Jul 16 05:55:33 MST 2014
Hi,

I know how to run individual functions of my own code from RAM (see here), but is there also a simple way to relocate an existing function in the CMSIS-DSP library to RAM without modifying the Library source code and recompiling it?

Guido

Re: Running a CMSIS-DSP-Library function from RAM

lpcware — Thu, 16 Jun 2016 01:33:09 GMT

Content originally posted in LPCWare by lpcxpresso-support on Wed Jul 16 07:17:55 MST 2014
You will need to modify the linker script or linker script template to explicitly include/exclude the appropriate code sections in the appropriate memory. For more information, see:

http://www.lpcware.com/content/faq/lpcxpresso/own-linker-scripts
http://www.lpcware.com/content/faq/lpcxpresso/linker-script-templates

But anyway, the attached project does exactly this using a linker script template. The key bits to note are that in the .text output section, the input section description:

        *(.text*)

has been changed to:

        *(EXCLUDE_FILE(*libCMSIS_DSPLIB_CM4.a:) .text*)

Then later in the script template, an extra .data output section has been added, to place the DSP functions into:

.data : ALIGN(4)
{
   FILL(0xff)
   . = ALIGN(4) ;
   *libCMSIS_DSPLIB_CM4.a:(.text*)
   . = ALIGN(4) ;
} >  ${DATA} AT>${CODE}

Check the map file after building to see where the code has been placed.

The actual code in the project is the standard CMSIS_DSP "arm_class_marks_example_f32.c" example. See the CMSIS documentation for details.

The project has been created for the LPC4337. But you should be able to copy the source into a project of your own for a different MCU, and also copy the linkscripts folder (and its template) into your own project too.

Note that in order to build this example, you will need to have imported the 'CMSIS_DSPLIB_CM4" project into your workspace too. For background information, see http://www.lpcware.com/content/faq/lpcxpresso/cmsis-dsp-library

Regards,
LPCXpresso Support

Re: Running a CMSIS-DSP-Library function from RAM

lpcware — Thu, 16 Jun 2016 01:33:10 GMT

Content originally posted in LPCWare by g_mocken on Thu Jul 24 01:49:17 MST 2014
Thanks a lot, using the provided link_template.ld seems to work, and the performance boost is impressive, too.

topic Re: Running a CMSIS-DSP-Library function from RAM in LPCXpresso IDE

Running a CMSIS-DSP-Library function from RAM

Re: Running a CMSIS-DSP-Library function from RAM

Re: Running a CMSIS-DSP-Library function from RAM